Circulation: cardiovascular difficulty
The failure to deliver adequate oxygen to the tissues:
·Heart rate disturbance: bradycardia, dysrhythmias.
·Decreased stroke volume: hypovolaemia; vasodilatation; poor contractility.
Cardiac fatigue due to:
·Excess volume load: from left-to-right cardiac lesions (ventricular septal defect (VSD), patent ductus arteriosus (PDA), atreriovenous (AV) canal), AV fistula, severe anaemia, hypervolaemia.
·Excess pressure load: from systemic vascular system (aortic stenosis, coarctation of the aorta, or hypertension) or pulmonary vascular system (pulmonary stenosis, pulmonary hypertension, chronic hypoventilation, or severe upper airway obstruction).
·Myocardial problems: including cardiomyopathy, myocarditis, myocardial ischaemia (anomalous coronary artery, cardiac thrombosis in Kawasaki), metabolic disorders.
·Excess myocardial demand: due to fever, thyrotoxicosis.
uncommon, but consider:
·Congenital heart block.
causes of hypertension are:
·Renal: glomerulonephritis; haemolytic–uraemic syndrome; pyelonephritis; obstructive nephropathy; vascular disease.
·Cardiac: coartation of the aorta.
·Neurological: infection; drugs; tumour; cerebral oedema.
·Endocrine: phaeochromocytoma; Cushing’s syndrome; corticosteroids; hyperthyroidism.
·Toxins and poisons.
·Primary essential hypertension.
main causes are food, medication, and insect bites. Life-threatening problems are:
·Respiratory: airway narrowing of upper and lower airway.
·CVS: shock, vasodilatation, and increased vascular permeability.
The causes include infection, rheumatologi-cal disorders, trauma, malignancy, and post-pericardiotomy syndrome.